Synthesis of an organic-inorganic hybrid material by solid state intercalation of 2-mercaptopyridine into Na-, Al(III)- and Co(II)-montmorillonite

The preparation of an organic-inorganic hybrid material by solid state intercalation of 2-mercaptopyridine (2Mpy) into Na-, Co(II)- and Al(III)-montmorillonite has been studied using a variety of techniques. The extension ofd 001from XRD proves that the intercalation of 2-mercaptopyridine into Na-, Co(II)- and Al(III)-mont occurs at ambient temperature in 5 mn. When the intercalated samples were heated at different temperatures, we found that the d001 gave different values. For instance, for intercalated Al(III)- and Co(II)-, d001 remained unchanged for a temperature under 500°C. However, for intercalated Na-mont, it shifted to 14 A for a temperature of 300° C, the washing of different samples with a methanol solution shifted thed 001of intercalated Na-mont to 14 A. However, for intercalated Al(III) and Co(II), it did not change. This proves that in the case of Na-mont, the molecules of 2-mercaptopyridine interact with the clay through hydrogen bindings and physical interactions. However, for Al(III) and Co(II), it forms coordination linking and physical interaction.13C NMR and FTIR spectroscopy have been employed for the characterization of the intercalation compounds. Tautomeric equilibrium between thiol and thione species of 2-mercaptopyridine must be taken into account to explain the arrangement of molecular aggregates and their particular orientation in the interlayer space. The isotherm of adsorption-desorption of nitrogen and topographic AFM images prove that intercalation of 2Mpy is accompanied by a total blockage of clay porosity and an increase in roughness.